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POGetting size of a specific byte array from an array of pointers to bytes
 

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  1. POGetting size of a specific byte array from an array of pointers to bytes
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    <p>In the following example c code, used in an <a href="http://arduino.cc" rel="nofollow noreferrer">Arduino</a> project, I am looking for the ability to get the size of a specific byte array within an array of pointers to bytes, for example </p> <pre><code> void setup() { Serial.begin(9600); // for debugging byte zero[] = {8, 169, 8, 128, 2,171,145,155,141,177,187,187,2,152,2,8,134,199}; byte one[] = {8, 179, 138, 138, 177 ,2,146, 8, 134, 8, 194,2,1,14,199,7, 145, 8,131, 8,158,8,187,187,191}; byte two[] = {29,7,1,8, 169, 8, 128, 2,171,145,155,141,177,187,187,2,152,2,8,134,199, 2, 2, 8, 179, 138, 138, 177 ,2,146, 8, 134, 8, 194,2,1,14,199,7, 145, 8,131, 8,158,8,187,187,191}; byte* numbers[3] = {zero, one, two }; function(numbers[1], sizeof(numbers[1])/sizeof(byte)); //doesn't work as desired, always passes 2 as the length function(numbers[1], 25); //this works } void loop() { } void function( byte arr[], int len ) { Serial.print("length: "); Serial.println(len); for (int i=0; i&lt;len; i++){ Serial.print("array element "); Serial.print(i); Serial.print(" has value "); Serial.println((int)arr[i]); } } </code></pre> <p>In this code, I understand that <code>sizeof(numbers[1])/sizeof(byte)</code> doesn't work because <code>numbers[1]</code> is a pointer and not the byte array value.</p> <p>Is there a way in this example that I can, at runtime, get at the length of a specific (runtime-determined) byte array within an array of pointers to bytes? Understand that I am limited to developing in c (or assembly) for an Arduino environment.</p> <p>Also open to other suggestions rather than the array of pointers to bytes. The overall objective is to organize lists of bytes which can be retrieved, with length, at runtime.</p>
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    1. USPat James
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    1. COHow are you going to, at runtime, get this byte array? Is it being read in from an external device or file? Or will it always be an array declared in code. If code, then ndim's solution will work. If external, you will have some sort of size already in hand from reading that file/source in order to size your dynamic array yes?
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      1. USMichael Dorgan
    2. COIt is all set in code. The external driver is a timer, with specific byte arrays used at specific times to make a speech synthesizer say things appropriate to the current clock timer value.
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